As the world warms, water - either too little or too much of it - is going to be the major problem for the United States, scientists and military experts said Monday. It will be a domestic problem, with states clashing over controls of rivers, and a national security problem as water shortages and floods worsen conflicts and terrorism elsewhere in the world, they said.

At home, especially in the Southwest, regions will need to find new sources of drinking water, the Great Lakes will shrink, fish and other species will be left high and dry, and coastal areas will on occasion be inundated because of sea-level rises and souped-up storms, U.S. scientists said.

The scientists released a 67-page chapter on North American climate effects, which is part of an international report on climate change impact.